A variety of designs have been commercialized or proposed for actuators in instruments that operate a tissue-engaging end effector (e.g., a pair of cooperating jaws in which one or both jaws pivot or otherwise move between open and closed positions). Examples of such instruments include tissue graspers, tissue clamps, needle graspers, tissue cutters, linear staplers, ligating clip appliers, and the like.
In some surgical applications, it is necessary or advantageous to apply relatively high squeezing forces. Thus, it would be desirable to provide an improved actuation system that can provide an amplification effect for increasing the force applied by the jaw (or other end effector) compared to the operator input force. It would also be beneficial if the system could accommodate designs wherein the reaction force or load is sensed by the operator. Such tactile feedback would be advantageous in delicate operations.
Some instruments, such as some clip appliers, include spring-biased or spring-actuated internal components which can create significant impact reactions within the instrument. This can produce undesirable noise and movement. Accordingly, it would be beneficial to provide an improved actuation system for moving a tissue end effector (e.g., jaws) in a controlled and quiet manner.
It would further be desirable to provide an improved actuation system having a reduced number of components, such as mechanical linkages, rachet mechanisms, and the like, so as to simplify fabrication and so as to minimize friction losses.
Finally, it would also be beneficial if such an improved system could be provided with sufficient capacity and strength to accommodate relatively high loads during operation of the instrument.
The present invention provides an improved actuation system which can be used to operate a surgical instrument and which can accommodate designs having the above-discussed benefits and features.